This undated page from NSA’s internal WikiInfo describes the Transform Engine Emulator (TEe) process for undermining VPNs: see the Der Spiegel story Prying Eyes: Inside the NSA’s War on Internet Security, 28 December 2014.

Slides from an NSA Turbulence presentation describe two of the agency’s specialised implants, aimed at compromising virtual private networks (VPNs) and online telephony (VOIP): see the Intercept article How the NSA Plans to Infect ‘Millions’ of Computers with Malware, 12 March 2014.

This undated page from NSA’s internal WikiInfo describes VALIANTSURF “the coverterm for the development of Data Network Cipher (DNC) exploitation capabilities in TURMOIL”: see the Der Spiegel story Prying Eyes: Inside the NSA’s War on Internet Security, 28 December 2014.

﻿VALIANTSURF - Wikiinfo
The accredited security level of this system is: TOP SECRET//SI-GAMMA/TALENT KEYHOLE//ORCON/PROPIN/RELIDO/REL TO USA, FVEY *
TOP SECRET1/SI/10RCON1REL TO USA, FVEY
...

This undated page from NSA’s internal WikiInfo describes POISONNUT and its role in attcks against VPNs: see the Der Spiegel story Prying Eyes: Inside the NSA’s War on Internet Security, 28 December 2014.